In the past few days, I’ve worked on finding a way to do static code analysis on JavaScript files.The resaon is that I want to apply some sort of binary and source code checking like FxCop and StyleCop provides for C#.

There exist some tools for linting JavaScript like JavaScript Lint, but linting only checks syntax and not implementation. To do that I found the Jscript compiler build into the .NET Framework to be just what I wanted. It compiles JavaScript and reports if it finds any errors.

To test it out, I wrote a simple C# class that takes an array of JavaScript files to compile. I then called the class from a unit test, so I could make the test fail if the compiler finds any errors with the script files. The class contains a single public method called Compile and here is a simplified example on how to use it from any unit testing framework. You can download the class at the bottom of this post.

What’s nice is that by doing compile time checking of JavaScripts, I get that extra little security that’s so hard to get when developing JavaScript heavy websites. The Microsoft JScript compiler isn’t perfect, so I still recommend using a linting tool as well. The two approaches cover different scenarios. I hope to have a very simple implementation on using a linting tool soon.

Download

Remember to add a reference to Microsoft.JScript in your Visual Studio project before using this class.